   and evaluate body **exprs**.
 
   Example:
-```
-(let-classifier
+  ```
+  (let-classifier
     (langid-baseline [inst]
        (let [attrib (weka/attribute-by-name inst \"langid-1-id\")
              val (.stringValue inst attrib)

  it doesn't take the `java.util.Random` instance"
  [inst & {:keys [train-fn test-fn randomize-fn]}]
  (let [train-state (atom nil)]
   (proxy [Instances] [inst]
     (randomize [rand]
       (log/infof "randominzing: %s with fn=%s" rand randomize-fn)
       (if randomize-fn (randomize-fn rand)))
     (trainCV [folds fold rand]
       (log/debugf "folds: %d, fold no: %d" folds fold)
       (let [res (proxy-super trainCV folds fold rand)]
         (if train-fn
           (train-fn res train-state inst folds fold)
           res)))
     (testCV [folds fold]
       (log/debugf "folds: %d, fold no: %d" folds fold)
       (let [res (proxy-super testCV folds fold)]
         (if test-fn
           (test-fn res train-state inst folds fold)
           res))))))

(defn instances
  "Create a new `weka.core.Instances` instance.

   :tree '("weka.classifiers.misc.HyperPipes"
           "weka.classifiers.trees.RandomTree"
           "weka.classifiers.trees.RandomForest"
                                        ;"weka.classifiers.trees.NBTree"
           "weka.classifiers.trees.REPTree")
   :zeror '("weka.classifiers.rules.ZeroR")
   :svm '("weka.classifiers.functions.LibSVM")
